The overall objective of our research program is to decipher the structure-function relationship for the human adenovirus DNA binding protei (DBP) and define the mechanistically how this protein performs several of its different functions. DBP is the paradigm for eukaryotic ssDNA binding proteins. Thus insights into its functions and how they are dictated by its structure will serve as an important model for this class of proteins. We will continue to use our genetic approach to study several aspects of DBP structure and function. The role(s) of phosphorylation in auto- enhancement and possibly in nuclear localization will be defined. The contributions made to nucleic acid binding and DNA replication by both DBP's presumptive metal binding finger and aa's in its DNA binding site will be determined. In addition ne mutations, particularly in the segment of the N-t domain which is responsible for regulating late gene expression and the virus' host range, will be isolated and characterized. The genetic approach is being combined with the biochemical characterization of the mutant-infected (transfected) cells or the mutant DBPs. For example, studies are proposed to determine whether DBP enhances its expression at the transcriptional level and if so via which promotor (E2aE or E2aL) and promotor element(s)? The region (aa's) of the protein involved in ssDNA binding is also being physically mapped; and proteins associated with DBP will be identified and characterized.